Elves are extremely long-lived -- the passing years are but a blink of an eye to them. What also sets them apart from us is the very narrow window during which they can procreate, and, as a natural consequence, their very low fertility. The Aen Seidhe believe this to be the main reason for their decline. As one of my elven friends put it, "Even though we fought like wolves, we lost to a race which fucks like rabbits.